Fluid Mechanics of Soil Gas Entry and Fate Within Buildings As Applied to Indoor Soil Gas Measurements and Mitigation

摘要

Tempering interpretations of short-term test data compared to known causes for fluctuations indoor concentration can result in meaningful and useful measurements. Fluctuations in soil gas entry are not random. There are known causes for effects that modulate when air movement occurs and the direction, magnitude, and mixing qualities of diverse air sources. Short-term measurements conducted with controls (e.g., closed-building conditions and measured in ground contact occupiable areas) are reproducible and most often result in test results that are usually well within one order of magnitude of yearlong concentrations in the lowest regions of the building. Tempering interpretations includes: a) considering test data in context with average buildings conditions across the year (or worst case conditions if short-term acute exposures are the concern); b) consideration for the context that unique conditions exist for any short-term period regardless if that period ranges from days to multiple months. Only additional testing conducted under alternate conditions can qualify the magnitude of any specific influence on test results; and c) only yearlong tests in lived-in portions of a building can quantify yearlong exposures.